This is an epidemiologic prospective study to identify biochemical, dietary and other factors related to cancer occurring among American Japanese men living in Hawaii. The proposal is focused on two specific cancer sites: the prostate and colon. Five specific aims will be addressed: l) to determine if dietary fat or vitamin A intake increases prostate cancer risk; 2) to study the association of serum levels of vitamin A and carotenoids with prostate cancer risk, using pre-diagnostic serum; 3) to see if elevated serum levels of adrenal androgens and other androgens (androsterone glucuronide and 5-alpha-androstane-3-alpha, 17- beta-diol glucuronide) increase prostate cancer risk; 4) to see if a high intake of dietary fat increases colon cancer risk; 5) to determine if high serum levels of vitamin D protect against colon cancer.